中文摘要：

运用ABAQUS有限元分析软件对基于位错密度的晶体塑性有限元方法（CPFEM）及其晶体塑性参数进行了深入的研究。结果表明,CPFEM晶体塑性本构可以准确地体现材料的力学性能。通过讨论不同晶体塑性参数,得到各个参数可以分别控制材料的屈服强度、硬化过程、剪切应变速率、极限强度等性能。此外,为了标定材料的晶体塑性参数引入多晶的代表体积单元（RVE）模型,并讨论了晶粒数以及晶粒规整度对于RVE模型的影响。结果表明,RVE模型的晶粒数达到临界值750个时能够体现等轴晶的宏观各向同性。结合晶体塑性RVE模拟和拉伸试验结果,对Inconel 718合金的晶体塑性参数进行标定,晶体塑性有限元的模拟结果和实验结果的误差小于5%。证明经过标定的晶体塑性参数可以准确反映Inconel 718的力学性能,也使得进一步研究该合金介观晶粒尺度的力学性能成为可能。

英文摘要：

Crystal plasticity finite element method （CPFEM） based on dislocation density and concerned para meters were investigated using ABAQUS. The crystal plasticity constitutive laws can reflect the mechanical properties accurately. The effect of crystal plasticity parameters on mechanical properties was discussed. It turns out that each parameter has unique effect that can control the yield stress, the hardening law, the shear strain rate as well as the ultimate strength. Representative volume element （RVE） model was introduced to calibrate these parameters. The effect of grain number and grain regularity on RVE model was studied. It is found that the critical grain number is 750 and that the RVE model can present the macro-isotropy for equiaxed polycrystals. The crystal plasticity parameters of Inconel 718 were calibrated with the comparison between RVE simulation and tensile test. After calibration, the difference between simulation and experiment is within 5%, which proves that the calibrated parameters can embody the mechanical properties of Inconel 718. Therefore, it is made possible to study the meso-scale mechanical properties at grain size.